K&P at Clyde Forks
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the K&P at Clyde Forks clear sky chart from 2005-11-06 to 2024-02-20.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	17% 10% 4 8% 6% 3 5% 4 5% 6% 31%	78228
	Night	16% 11% 4 8% 6% 3 5% 4 5% 6% 31%	80939
Transparency	Day	52% 7% 11% 18% 10% 1	77933
	Night	53% 7% 11% 18% 9% 1	80768
Seeing	Day	23% 17% 31% 18% 8% 2	13431
	Night	22% 15% 31% 23% 8% 1	22762

By Month

Percentage Cloud Cover NE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	14% 16% 6% 11% 9% 4 5% 5% 4 5% 21%	2517
	11th to 20th	Day	12% 15% 8% 12% 9% 4 6% 3 4 4 21%	2520
	21st to end	Day	16% 21% 7% 13% 8% 4 4 3 3 4 16%	2978
February	1st to 10th	Day	13% 14% 6% 12% 9% 4 5% 5% 5% 6% 22%	1710
	11th to 20th	Day	11% 14% 6% 10% 7% 4 5% 4 4 6% 28%	1654
	21st to end	Day	18% 15% 4 9% 7% 5% 5% 5% 4 5% 24%	1449
March	1st to 10th	Day	14% 13% 5% 11% 8% 4 5% 4 4 5% 28%	1844
	11th to 20th	Day	14% 13% 5% 8% 8% 4 5% 5% 4 4 29%	1980
	21st to end	Day	17% 10% 5% 7% 5% 2 4 4 4 5% 37%	2258
April	1st to 10th	Day	20% 13% 4 6% 5% 3 4 4 5% 5% 31%	2160
	11th to 20th	Day	21% 9% 4 5% 5% 2 3 4 4 5% 38%	2134
	21st to end	Day	22% 11% 3 6% 5% 3 5% 4 4 5% 32%	2281
May	1st to 10th	Day	19% 8% 3 6% 6% 3 4 4 5% 5% 35%	2520
	11th to 20th	Day	16% 8% 3 7% 5% 3 4 4 4 7% 38%	2478
	21st to end	Day	14% 7% 3 5% 7% 4 5% 5% 6% 7% 38%	2725
June	1st to 10th	Day	21% 8% 3 7% 6% 4 5% 5% 5% 6% 31%	2520
	11th to 20th	Day	15% 6% 3 6% 5% 4 5% 5% 6% 9% 38%	2520
	21st to end	Day	16% 7% 3 7% 7% 4 6% 5% 6% 7% 33%	2520
July	1st to 10th	Day	11% 6% 3 5% 6% 4 6% 6% 6% 8% 39%	2520
	11th to 20th	Day	12% 6% 3 6% 6% 3 5% 5% 8% 10% 37%	2520
	21st to end	Day	12% 5% 3 6% 5% 4 6% 6% 8% 9% 37%	2744
August	1st to 10th	Day	12% 6% 3 6% 7% 3 5% 5% 6% 7% 38%	2408
	11th to 20th	Day	13% 6% 2 6% 6% 4 6% 5% 6% 8% 37%	2303
	21st to end	Day	15% 6% 3 5% 6% 3 5% 5% 7% 8% 36%	2384
September	1st to 10th	Day	15% 6% 2 5% 6% 3 5% 5% 5% 8% 39%	2160
	11th to 20th	Day	13% 5% 2 5% 5% 3 5% 5% 6% 7% 45%	2160
	21st to end	Day	17% 7% 2 6% 6% 3 4 4 6% 7% 39%	1904
October	1st to 10th	Day	21% 8% 4 6% 6% 4 4 4 4 6% 34%	1800
	11th to 20th	Day	22% 10% 4 7% 6% 3 5% 4 5% 6% 27%	1800
	21st to end	Day	26% 10% 4 8% 6% 3 4 4 4 5% 25%	1881
November	1st to 10th	Day	13% 11% 3 7% 7% 4 5% 5% 5% 7% 34%	1638
	11th to 20th	Day	17% 12% 6% 8% 6% 3 5% 4 5% 5% 28%	1520
	21st to end	Day	20% 14% 7% 9% 8% 4 4 4 4 6% 20%	1520
December	1st to 10th	Day	19% 19% 7% 10% 7% 3 5% 4 4 4 16%	1520
	11th to 20th	Day	19% 14% 6% 9% 6% 3 4 4 4 5% 26%	1906
	21st to end	Day	27% 17% 6% 13% 6% 2 3 2 3 3 19%	2772
January	1st to 10th	Night	16% 13% 8% 12% 9% 4 5% 4 5% 6% 18%	4429
	11th to 20th	Night	11% 14% 5% 12% 12% 5% 6% 5% 5% 6% 21%	4440
	21st to end	Night	16% 18% 8% 10% 7% 5% 5% 4 3 4 19%	4661
February	1st to 10th	Night	13% 15% 6% 11% 7% 4 5% 4 6% 6% 23%	2470
	11th to 20th	Night	12% 13% 6% 9% 7% 4 4 4 5% 5% 30%	2397
	21st to end	Night	13% 12% 4 8% 8% 4 5% 5% 5% 5% 29%	1806
March	1st to 10th	Night	15% 12% 5% 9% 8% 3 5% 3 4 5% 30%	2101
	11th to 20th	Night	14% 13% 6% 7% 5% 3 4 3 5% 7% 33%	1979
	21st to end	Night	15% 9% 3 7% 6% 3 5% 5% 4 6% 38%	2096
April	1st to 10th	Night	20% 10% 4 6% 6% 3 3 4 5% 5% 34%	1800
	11th to 20th	Night	19% 8% 4 6% 5% 3 4 4 4 6% 37%	1775
	21st to end	Night	19% 10% 4 7% 5% 3 4 5% 5% 6% 32%	1694
May	1st to 10th	Night	19% 9% 3 6% 4 3 5% 5% 4 6% 37%	1440
	11th to 20th	Night	17% 6% 3 5% 5% 2 5% 4 5% 7% 41%	1415
	21st to end	Night	13% 5% 2 5% 4 3 5% 5% 5% 9% 44%	1550
June	1st to 10th	Night	16% 5% 3 6% 7% 3 4 6% 7% 7% 35%	1440
	11th to 20th	Night	12% 6% 2 7% 6% 3 4 5% 5% 6% 43%	1440
	21st to end	Night	15% 7% 3 5% 5% 3 5% 4 6% 9% 37%	1440
July	1st to 10th	Night	9% 4 3 6% 5% 3 5% 5% 5% 8% 46%	1440
	11th to 20th	Night	10% 5% 3 5% 5% 4 4 4 6% 9% 44%	1440
	21st to end	Night	10% 4 2 5% 5% 4 5% 6% 6% 9% 45%	1574
August	1st to 10th	Night	9% 5% 2 6% 5% 3 5% 6% 6% 7% 45%	1528
	11th to 20th	Night	9% 5% 2 6% 5% 3 5% 5% 5% 8% 45%	1598
	21st to end	Night	11% 6% 3 5% 5% 3 5% 4 5% 8% 45%	1952
September	1st to 10th	Night	12% 6% 2 5% 5% 2 4 4 6% 7% 46%	1800
	11th to 20th	Night	15% 5% 2 3 4 3 3 4 4 7% 49%	1800
	21st to end	Night	16% 7% 2 5% 5% 2 3 5% 5% 6% 43%	2052
October	1st to 10th	Night	18% 9% 3 5% 5% 2 4 5% 5% 6% 38%	2160
	11th to 20th	Night	19% 10% 4 7% 6% 3 4 4 5% 6% 30%	2160
	21st to end	Night	22% 11% 4 7% 7% 3 4 4 5% 7% 27%	2474
November	1st to 10th	Night	17% 11% 3 7% 4 3 4 4 4 5% 36%	2436
	11th to 20th	Night	17% 11% 4 7% 7% 3 5% 5% 5% 6% 29%	2660
	21st to end	Night	19% 15% 5% 8% 7% 3 4 4 4 7% 24%	2660
December	1st to 10th	Night	18% 18% 6% 10% 8% 3 5% 5% 5% 5% 18%	2660
	11th to 20th	Night	20% 16% 5% 9% 7% 3 4 4 3 5% 25%	3288
	21st to end	Night	27% 18% 5% 11% 6% 3 4 3 3 4 15%	4884

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	63% 10% 11% 9% 6% 1	2518
	11th to 20th	Day	66% 7% 10% 10% 7% 1	2520
	21st to end	Day	73% 5% 7% 9% 6% 1	2978
February	1st to 10th	Day	63% 6% 9% 16% 5% 1	1710
	11th to 20th	Day	57% 5% 11% 15% 10% 1	1663
	21st to end	Day	62% 6% 9% 11% 10% 1	1449
March	1st to 10th	Day	58% 5% 9% 15% 10% 2	1847
	11th to 20th	Day	57% 5% 11% 14% 11% 2	1980
	21st to end	Day	51% 4 8% 18% 14% 6%	2258
April	1st to 10th	Day	54% 5% 8% 18% 12% 3	2160
	11th to 20th	Day	50% 5% 7% 20% 16% 2	2134
	21st to end	Day	54% 6% 8% 15% 14% 4	2281
May	1st to 10th	Day	49% 6% 9% 17% 15% 4	2520
	11th to 20th	Day	46% 5% 9% 21% 17% 3	2482
	21st to end	Day	45% 7% 12% 20% 14% 2	2725
June	1st to 10th	Day	53% 7% 9% 18% 12% 1	2520
	11th to 20th	Day	43% 8% 11% 22% 13% 3	2520
	21st to end	Day	48% 8% 13% 19% 11% 1	2520
July	1st to 10th	Day	39% 8% 11% 27% 14% 1	2450
	11th to 20th	Day	38% 9% 17% 24% 11% 1	2445
	21st to end	Day	41% 9% 13% 26% 10%	2591
August	1st to 10th	Day	42% 9% 14% 24% 10%	2394
	11th to 20th	Day	43% 9% 16% 22% 9% 1	2303
	21st to end	Day	42% 7% 14% 25% 11% 1	2384
September	1st to 10th	Day	41% 8% 13% 26% 11%	2160
	11th to 20th	Day	38% 7% 12% 28% 14%	2160
	21st to end	Day	45% 7% 14% 25% 9%	1904
October	1st to 10th	Day	52% 6% 10% 21% 11% 1	1800
	11th to 20th	Day	56% 8% 13% 17% 6% 1	1800
	21st to end	Day	62% 6% 10% 15% 6% 1	1881
November	1st to 10th	Day	49% 7% 15% 21% 7% 1	1638
	11th to 20th	Day	57% 7% 11% 15% 9% 1	1520
	21st to end	Day	65% 8% 10% 9% 7% 1	1520
December	1st to 10th	Day	71% 7% 9% 9% 3	1520
	11th to 20th	Day	61% 6% 14% 12% 6%	1906
	21st to end	Day	73% 4 6% 13% 4	2772
January	1st to 10th	Night	65% 10% 12% 11% 3	4429
	11th to 20th	Night	63% 8% 13% 11% 4 1	4440
	21st to end	Night	69% 6% 9% 9% 6% 1	4661
February	1st to 10th	Night	61% 5% 11% 16% 6% 1	2470
	11th to 20th	Night	57% 5% 11% 19% 8% 1	2399
	21st to end	Night	55% 6% 11% 17% 10% 1	1806
March	1st to 10th	Night	57% 4 12% 16% 10% 2	2111
	11th to 20th	Night	52% 4 13% 18% 11% 2	1980
	21st to end	Night	47% 5% 9% 20% 15% 4	2096
April	1st to 10th	Night	52% 5% 9% 18% 14% 2	1800
	11th to 20th	Night	48% 5% 8% 22% 15% 2	1775
	21st to end	Night	53% 5% 7% 17% 16% 3	1694
May	1st to 10th	Night	48% 6% 6% 20% 16% 4	1440
	11th to 20th	Night	42% 6% 9% 23% 17% 3	1416
	21st to end	Night	36% 8% 15% 19% 19% 3	1551
June	1st to 10th	Night	45% 8% 12% 22% 11% 1	1440
	11th to 20th	Night	40% 7% 11% 23% 17% 2	1440
	21st to end	Night	43% 10% 15% 19% 12% 1	1440
July	1st to 10th	Night	34% 9% 11% 25% 18% 3	1400
	11th to 20th	Night	38% 7% 12% 30% 13%	1392
	21st to end	Night	34% 8% 18% 27% 13% 1	1486
August	1st to 10th	Night	36% 10% 17% 24% 12% 1	1518
	11th to 20th	Night	35% 9% 16% 29% 10% 1	1598
	21st to end	Night	36% 7% 16% 28% 12% 1	1952
September	1st to 10th	Night	35% 9% 14% 27% 14% 1	1800
	11th to 20th	Night	35% 7% 14% 33% 11% 1	1800
	21st to end	Night	41% 7% 12% 31% 8% 1	2052
October	1st to 10th	Night	46% 7% 11% 21% 14%	2160
	11th to 20th	Night	53% 8% 13% 18% 8%	2160
	21st to end	Night	57% 7% 12% 15% 9%	2474
November	1st to 10th	Night	50% 6% 14% 20% 10%	2436
	11th to 20th	Night	54% 8% 11% 17% 8% 1	2660
	21st to end	Night	61% 7% 12% 15% 5%	2660
December	1st to 10th	Night	68% 7% 10% 12% 3	2660
	11th to 20th	Night	63% 5% 9% 14% 8% 1	3288
	21st to end	Night	74% 5% 7% 11% 3	4884

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	23% 22% 37% 15% 3	180
	11th to 20th	Day	30% 21% 34% 12% 3	180
	21st to end	Day	23% 21% 38% 13% 5%	258
February	1st to 10th	Day	29% 28% 31% 8% 3	270
	11th to 20th	Day	30% 27% 39% 3 1	267
	21st to end	Day	33% 26% 31% 9% 1	315
March	1st to 10th	Day	25% 22% 37% 13% 3	420
	11th to 20th	Day	29% 21% 32% 15% 3	420
	21st to end	Day	32% 22% 27% 13% 5%	462
April	1st to 10th	Day	30% 23% 29% 12% 5%	420
	11th to 20th	Day	33% 20% 20% 17% 8% 1	412
	21st to end	Day	29% 20% 32% 10% 7% 1	420
May	1st to 10th	Day	26% 17% 31% 17% 6% 3	423
	11th to 20th	Day	21% 18% 32% 20% 6% 2	447
	21st to end	Day	19% 16% 33% 19% 9% 3	485
June	1st to 10th	Day	24% 15% 34% 19% 8%	450
	11th to 20th	Day	16% 17% 29% 24% 12% 2	450
	21st to end	Day	19% 11% 36% 20% 12% 2	450
July	1st to 10th	Day	11% 9% 30% 35% 13% 3	445
	11th to 20th	Day	14% 12% 30% 26% 14% 4	444
	21st to end	Day	15% 9% 35% 27% 11% 3	488
August	1st to 10th	Day	15% 7% 33% 29% 12% 5%	446
	11th to 20th	Day	12% 9% 29% 29% 15% 6%	439
	21st to end	Day	15% 12% 31% 23% 12% 6%	495
September	1st to 10th	Day	15% 11% 32% 22% 13% 7%	450
	11th to 20th	Day	14% 12% 27% 24% 14% 9%	450
	21st to end	Day	19% 15% 30% 18% 12% 6%	450
October	1st to 10th	Day	24% 18% 26% 19% 10% 4	450
	11th to 20th	Day	28% 23% 29% 16% 4 2	450
	21st to end	Day	32% 18% 29% 16% 4	445
November	1st to 10th	Day	25% 20% 31% 18% 6% 1	332
	11th to 20th	Day	28% 21% 33% 12% 4 2	180
	21st to end	Day	29% 24% 32% 9% 4 1	180
December	1st to 10th	Day	32% 21% 35% 10% 2	180
	11th to 20th	Day	31% 28% 30% 7% 3 1	180
	21st to end	Day	30% 25% 30% 12% 3 1	198
January	1st to 10th	Night	24% 22% 35% 16% 3	760
	11th to 20th	Night	26% 22% 30% 18% 4 1	760
	21st to end	Night	20% 17% 37% 21% 5%	836
February	1st to 10th	Night	23% 20% 36% 19% 2	760
	11th to 20th	Night	22% 21% 42% 12% 3	742
	21st to end	Night	23% 22% 34% 18% 3	592
March	1st to 10th	Night	26% 19% 33% 19% 3	720
	11th to 20th	Night	25% 22% 32% 17% 4 1	720
	21st to end	Night	22% 17% 32% 21% 7%	792
April	1st to 10th	Night	27% 18% 31% 20% 3	720
	11th to 20th	Night	25% 21% 28% 19% 6%	711
	21st to end	Night	24% 16% 28% 24% 7%	614
May	1st to 10th	Night	22% 10% 31% 26% 10% 1	360
	11th to 20th	Night	21% 10% 34% 28% 7%	354
	21st to end	Night	12% 9% 38% 29% 12%	389
June	1st to 10th	Night	16% 11% 32% 32% 9%	360
	11th to 20th	Night	14% 12% 33% 30% 11% 1	360
	21st to end	Night	19% 9% 28% 29% 13%	360
July	1st to 10th	Night	7% 9% 31% 37% 15% 1	350
	11th to 20th	Night	12% 5% 30% 40% 12% 1	348
	21st to end	Night	10% 3 32% 42% 12% 1	394
August	1st to 10th	Night	11% 6% 25% 40% 18%	454
	11th to 20th	Night	11% 4 26% 37% 19% 3	534
	21st to end	Night	14% 7% 31% 29% 16% 2	764
September	1st to 10th	Night	16% 8% 31% 27% 17% 1	720
	11th to 20th	Night	18% 7% 24% 30% 18% 3	720
	21st to end	Night	18% 12% 24% 25% 18% 2	720
October	1st to 10th	Night	23% 13% 27% 23% 12% 2	720
	11th to 20th	Night	26% 15% 32% 18% 8% 1	720
	21st to end	Night	28% 17% 29% 21% 5%	792
November	1st to 10th	Night	26% 15% 32% 21% 6% 1	740
	11th to 20th	Night	24% 20% 32% 15% 8% 1	760
	21st to end	Night	31% 18% 27% 18% 5%	760
December	1st to 10th	Night	28% 19% 33% 16% 3	760
	11th to 20th	Night	27% 20% 31% 19% 2 1	760
	21st to end	Night	33% 18% 31% 16% 3	836

Page generated at 2024-02-17 06:28:36. Version ac07

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